Pipe such as cast iron, clay or ductile metal pipe has been used for connecting homes and creating networks for utilities such as water, sewer, or gas, etc. As pipes become old, they may crack or break, or for some other reason require replacement.
A technique know as pipe bursting is currently used as a convenient method to replace underground pipe without the need to dig up the pipe to be replaced. A pipe breaking device, such as an expander or a mole, is pulled by a cable through the existing pipe while it is still underground. The expander is designed to break, or burst the pipe, and at the same time to expand the broken pieces of the pipe into the surrounding soil. The expansion of the broken pipe allows the expander to pull a replacement pipe into place.
Bursting heads have been designed with various features such as expander cones, cutting blades, and wheel cutters to more effectively burst pipes and pull in replacement pipes. However, several pipe breaking devices including these or other features are needed to match conditions of a particular job such as, varying soil conditions, varying pipe materials, etc.
What is needed is an inexpensive and versatile expander design that provides flexibility to deal with varying job conditions. What is also needed is an improved expander design that increases the speed and decreases the power needed during a pipe bursting operation.